The present invention relates to the field of scales for weighing cargo carried by a truck or other vehicle. More particularly, this invention relates to a portable, modular, drive-over scale that can quickly be assembled without the use of heavy equipment in a field or any other area where cargo is to be weighed. The scale of this invention advantageously adapts to accurately weigh trailers or vehicles having single and/or tandem axles and single and/or dual inboard and outboard wheels.
It is often desirable to determine the weight of the cargo carried by a trailer or vehicle. Transportation laws provide penalties if a vehicle exceeds established weight restrictions for roads and bridges. In the case of agricultural products, payment may be based on the weight of the product or cargo delivered. Therefore, it is very important to accurately determine the weight of the cargo. Grain elevators and highway weigh stations typically utilize fixed platform scales with large, heavy platforms that extend over conventional weighing mechanisms located in a pit below the platform. The platform is usually constructed of heavy gauge structural steel and is at least 7xe2x80x2long and 10xe2x80x2, wide in order to accommodate the tandem axles of a semi-tractor trailer.
For various reasons, including avoiding the risk of fines for exceeding legal weight limits, it is often desirable to check the weight of a cargo-carrying vehicle in the field. To meet this need, xe2x80x9cportablexe2x80x9d platform scale systems, such as the J-STAR 7xe2x80x2xc3x9710xe2x80x2 Platform Scale System, have been developed and used for many years. The J-STAR 7xe2x80x2xc3x9710xe2x80x2 Platform Scale System includes a low profile rectangular scale housing with weigh beams bolted to a heavy gauge structural steel platform. A three-point tractor hitch lift attachment and detachable ramps are included with some models, but the housing ultimately supports the scale platform during use. A portable indicator stand holds a microprocessor-based electronic scale indicator that also controls the weighing operation. The indicator is powered by a 12-volt DC battery. The indicator is electrically connected to the strain gauge load cells associated with the weigh beams.
The J-STAR scale system can weigh cargo in the field, but has some shortcomings. First, the device generally has to be placed on a large area with a smooth, level surface to obtain the most accurate results. Smooth, level surfaces are not always available in the field. Second, the size and weight of the xe2x80x9cportablexe2x80x9d platform assembly make it impossible for a person to position the assembly without the assistance of heavy equipment, such as a tractor or forklift. Such equipment is not always readily available for use. Third, the 7xe2x80x2xc3x9710xe2x80x2 platform scale assembly requires considerable space for storage and transportation. Fourth, the bolting of the platform to the weigh bar(s) tends to leave undesirable ridges or irregularities in the scale platform. Thus, it can be seen that there is a need for an improved portable platform scale that is truly portable.
Therefore, a primary objective of the present invention is the provision of an improved platform scale.
A further objective of the present invention is the provision of a portable platform scale that does not require a level weighing surface to provide accurate results.
A further objective of this invention is the provision of a portable platform scale that is modular in design and can be quickly assembled manually without the use of a lifting device.
A further objective of this invention is the provision of a portable platform scale that has an interlocking I-beam construction.
A further objective of this invention is the provision of a portable platform scale wherein the scale platform is supported as a simple beam by a pair of ramps.
A further objective of this invention is the provision of a portable platform scale wherein the scale platform interlocks with the ramp or a coupling device by a connection that utilizes a cradle and an upright post on the ramp or coupling device, the post being received by a hole in the weigh bar attached to the scale platform.
These and other objectives will be apparent from the drawings, as well as from the description and claims that follow.
The present invention relates to the field of scales for weighing cargo carried by a vehicle. More particularly, this invention relates to a portable, modular, drive-over scale system that includes at least one portable scale platform, and more preferably two side-by-side platforms, detachably connected to and vertically supported by a pair of movable forward and rear ramps.
The scale platforms are vertically supported in a trough formed on an upright plate member of the ramps. A bar rigidly attached to the underside of the scale platform rests in the trough. Advantageously, the support bar can be a weigh bar equipped with strain gauges thereon. The bar has a vertical hole therethrough that slidably receives an upright post formed on the ramp. Thus, the scale platform is detachably connected to the ramp.
A coupling with a similar trough and connector post structure can be used to connect and support the scale platforms in an end-for-end arrangement to construct longer scales.